The present invention relates generally to wireless receivers, and more particularly to dual-carrier wireless terminal receivers for Evolved EDGE.
EDGE (Enhanced Data Rates for GSM Evolution) is a wireless network protocol that provides increased capacity, data transmission rates, and/or data transmission reliability over conventional GSM networks. EDGE uses the same TDMA frame structure, logic channel, and 200 kHz carrier bandwidth as GSM. Thus, in most instances, implementing EDGE requires a simple upgrade to an existing GSM network.
EDGE was initially introduced in the United States in 2003, and quickly gained in popularity. As of May 2007, 223 commercial GSM/EDGE networks exist in 113 countries, out of 287 mobile network operator commitments in 142 countries (source: Global mobile Suppliers Association). While EDGE provides improved performance over conventional GSM, e.g., data speeds up to 200 kb/s, further improvements to EDGE, known as “Evolved EDGE,” are currently under development by the 3rd-Generation Partnership Project (3GPP). (For details, see 3GPP TR 45.912, “Feasibility study for evolved GSM/EDGE Radio Access Network (GERAN),” v. 7.2.0, Mar. 20, 2007, available as of the filing date of the present application at www.3gpp.org/FTP/Specs/html-info/45912.htm, hereinafter referred to as “Evolved EDGE Feasibility Study.”) With enhancements including receiver diversity, higher-order modulation, and a new dual-carrier mode, Evolved EDGE promises data rates exceeding 1 Mb/second under some circumstances. Because Evolved EDGE also uses the same TDMA frame structure, logic channels, and carrier bandwidth as GSM networks, Evolved EDGE may also easily be implemented on existing GSM networks. However, new mobile terminals must be designed to fully exploit these improvements. Currently, wireless terminal vendors are reluctant to implement dual-carrier Evolved EDGE in wireless terminals due to expected impacts on radio architecture. Thus, there remains a need for an improved wireless terminal that is compatible with not only the existing GSM and EDGE networks, but is also compatible with Evolved EDGE networks.